[PATCH 08/10] UBI: Add fastmap support to the WL sub-system

From: Richard Weinberger
Date: Mon Sep 24 2012 - 14:33:00 EST

To make fastmap possible the WL sub-system needs some
changes.
Mostly to support fastmaps pools.

Signed-off-by: Richard Weinberger <richard@xxxxxx>
---
drivers/mtd/ubi/wl.c | 576 ++++++++++++++++++++++++++++++++++++++++++++++----
1 files changed, 531 insertions(+), 45 deletions(-)

diff --git a/drivers/mtd/ubi/wl.c b/drivers/mtd/ubi/wl.c
index f4d06db..2439f69 100644
--- a/drivers/mtd/ubi/wl.c
+++ b/drivers/mtd/ubi/wl.c
@@ -141,6 +141,42 @@ static int self_check_in_wl_tree(const struct ubi_device *ubi,
static int self_check_in_pq(const struct ubi_device *ubi,
struct ubi_wl_entry *e);

+#ifdef CONFIG_MTD_UBI_FASTMAP
+/**
+ * update_fastmap_work_fn - calls ubi_update_fastmap from a work queue
+ * @wrk: the work description object
+ */
+static void update_fastmap_work_fn(struct work_struct *wrk)
+{
+ struct ubi_device *ubi = container_of(wrk, struct ubi_device, fm_work);
+ ubi_update_fastmap(ubi);
+}
+
+/**
+ * ubi_ubi_is_fm_block - returns 1 if a PEB is currently used in a fastmap.
+ * @ubi: UBI device description object
+ * @pnum: the to be checked PEB
+ */
+static int ubi_is_fm_block(struct ubi_device *ubi, int pnum)
+{
+ int i;
+
+ if (!ubi->fm)
+ return 0;
+
+ for (i = 0; i < ubi->fm->used_blocks; i++)
+ if (ubi->fm->e[i]->pnum == pnum)
+ return 1;
+
+ return 0;
+}
+#else
+static int ubi_is_fm_block(struct ubi_device *ubi, int pnum)
+{
+ return 0;
+}
+#endif
+
/**
* wl_tree_add - add a wear-leveling entry to a WL RB-tree.
* @e: the wear-leveling entry to add
@@ -237,18 +273,16 @@ static int produce_free_peb(struct ubi_device *ubi)
{
int err;

- spin_lock(&ubi->wl_lock);
while (!ubi->free.rb_node) {
spin_unlock(&ubi->wl_lock);

dbg_wl("do one work synchronously");
err = do_work(ubi);
- if (err)
- return err;

spin_lock(&ubi->wl_lock);
+ if (err)
+ return err;
}
- spin_unlock(&ubi->wl_lock);

return 0;
}
@@ -315,16 +349,18 @@ static void prot_queue_add(struct ubi_device *ubi, struct ubi_wl_entry *e)

/**
* find_wl_entry - find wear-leveling entry closest to certain erase counter.
+ * @ubi: UBI device description object
* @root: the RB-tree where to look for
* @diff: maximum possible difference from the smallest erase counter
*
* This function looks for a wear leveling entry with erase counter closest to
* min + @diff, where min is the smallest erase counter.
*/
-static struct ubi_wl_entry *find_wl_entry(struct rb_root *root, int diff)
+static struct ubi_wl_entry *find_wl_entry(struct ubi_device *ubi,
+ struct rb_root *root, int diff)
{
struct rb_node *p;
- struct ubi_wl_entry *e;
+ struct ubi_wl_entry *e, *prev_e = NULL;
int max;

e = rb_entry(rb_first(root), struct ubi_wl_entry, u.rb);
@@ -339,35 +375,144 @@ static struct ubi_wl_entry *find_wl_entry(struct rb_root *root, int diff)
p = p->rb_left;
else {
p = p->rb_right;
+ prev_e = e;
e = e1;
}
}

+#ifdef CONFIG_MTD_UBI_FASTMAP
+ /* If no fastmap has been written and this WL entry can be used
+ * as anchor PEB, hold it back and return the second best WL entry
+ * such that fastmap can use the anchor PEB later. */
+ if (prev_e && !ubi->fm_disabled &&
+ !ubi->fm && e->pnum < UBI_FM_MAX_START)
+ return prev_e;
+#endif
return e;
}

/**
- * ubi_wl_get_peb - get a physical eraseblock.
+ * find_mean_wl_entry - find wear-leveling entry with medium erase counter.
+ * @ubi: UBI device description object
+ * @root: the RB-tree where to look for
+ *
+ * This function looks for a wear leveling entry with medium erase counter,
+ * but not greater or equivalent than the lowest erase counter plus
+ * %WL_FREE_MAX_DIFF/2.
+ */
+static struct ubi_wl_entry *find_mean_wl_entry(struct ubi_device *ubi,
+ struct rb_root *root)
+{
+ struct ubi_wl_entry *e, *first, *last;
+
+ first = rb_entry(rb_first(root), struct ubi_wl_entry, u.rb);
+ last = rb_entry(rb_last(root), struct ubi_wl_entry, u.rb);
+
+ if (last->ec - first->ec < WL_FREE_MAX_DIFF) {
+ e = rb_entry(root->rb_node, struct ubi_wl_entry, u.rb);
+
+#ifdef CONFIG_MTD_UBI_FASTMAP
+ /* If no fastmap has been written and this WL entry can be used
+ * as anchor PEB, hold it back and return the second best
+ * WL entry such that fastmap can use the anchor PEB later. */
+ if (e && !ubi->fm_disabled && !ubi->fm &&
+ e->pnum < UBI_FM_MAX_START)
+ e = rb_entry(rb_next(root->rb_node),
+ struct ubi_wl_entry, u.rb);
+#endif
+ } else
+ e = find_wl_entry(ubi, root, WL_FREE_MAX_DIFF/2);
+
+ return e;
+}
+
+#ifdef CONFIG_MTD_UBI_FASTMAP
+/**
+ * find_anchor_wl_entry - find wear-leveling entry to used as anchor PEB.
+ * @root: the RB-tree where to look for
+ */
+static struct ubi_wl_entry *find_anchor_wl_entry(struct rb_root *root)
+{
+ struct rb_node *p;
+ struct ubi_wl_entry *e, *victim = NULL;
+ int max_ec = UBI_MAX_ERASECOUNTER;
+
+ ubi_rb_for_each_entry(p, e, root, u.rb) {
+ if (e->pnum < UBI_FM_MAX_START && e->ec < max_ec) {
+ victim = e;
+ max_ec = e->ec;
+ }
+ }
+
+ return victim;
+}
+
+static int anchor_pebs_avalible(struct rb_root *root)
+{
+ struct rb_node *p;
+ struct ubi_wl_entry *e;
+
+ ubi_rb_for_each_entry(p, e, root, u.rb)
+ if (e->pnum < UBI_FM_MAX_START)
+ return 1;
+
+ return 0;
+}
+
+/**
+ * ubi_wl_get_fm_peb - find a physical erase block with a given maximal number.
+ * @ubi: UBI device description object
+ * @anchor: This PEB will be used as anchor PEB by fastmap
+ *
+ * The function returns a physical erase block with a given maximal number
+ * and removes it from the wl subsystem.
+ * Must be called with wl_lock held!
+ */
+struct ubi_wl_entry *ubi_wl_get_fm_peb(struct ubi_device *ubi, int anchor)
+{
+ struct ubi_wl_entry *e = NULL;
+
+ if (!ubi->free.rb_node || (ubi->free_count - ubi->beb_rsvd_pebs < 1))
+ goto out;
+
+ if (anchor)
+ e = find_anchor_wl_entry(&ubi->free);
+ else
+ e = find_mean_wl_entry(ubi, &ubi->free);
+
+ if (!e)
+ goto out;
+
+ self_check_in_wl_tree(ubi, e, &ubi->free);
+
+ /* remove it from the free list,
+ * the wl subsystem does no longer know this erase block */
+ rb_erase(&e->u.rb, &ubi->free);
+ ubi->free_count--;
+out:
+ return e;
+}
+#endif
+
+/**
+ * __wl_get_peb - get a physical eraseblock.
* @ubi: UBI device description object
*
* This function returns a physical eraseblock in case of success and a
* negative error code in case of failure. Might sleep.
*/
-int ubi_wl_get_peb(struct ubi_device *ubi)
+static int __wl_get_peb(struct ubi_device *ubi)
{
int err;
- struct ubi_wl_entry *e, *first, *last;
+ struct ubi_wl_entry *e;

retry:
- spin_lock(&ubi->wl_lock);
if (!ubi->free.rb_node) {
if (ubi->works_count == 0) {
- ubi_assert(list_empty(&ubi->works));
ubi_err("no free eraseblocks");
- spin_unlock(&ubi->wl_lock);
+ ubi_assert(list_empty(&ubi->works));
return -ENOSPC;
}
- spin_unlock(&ubi->wl_lock);

err = produce_free_peb(ubi);
if (err < 0)
@@ -375,13 +520,11 @@ retry:
goto retry;
}

- first = rb_entry(rb_first(&ubi->free), struct ubi_wl_entry, u.rb);
- last = rb_entry(rb_last(&ubi->free), struct ubi_wl_entry, u.rb);
-
- if (last->ec - first->ec < WL_FREE_MAX_DIFF)
- e = rb_entry(ubi->free.rb_node, struct ubi_wl_entry, u.rb);
- else
- e = find_wl_entry(&ubi->free, WL_FREE_MAX_DIFF/2);
+ e = find_mean_wl_entry(ubi, &ubi->free);
+ if (!e) {
+ ubi_err("no free eraseblocks");
+ return -ENOSPC;
+ }

self_check_in_wl_tree(ubi, e, &ubi->free);

@@ -390,10 +533,14 @@ retry:
* be protected from being moved for some time.
*/
rb_erase(&e->u.rb, &ubi->free);
+ ubi->free_count--;
dbg_wl("PEB %d EC %d", e->pnum, e->ec);
+#ifndef CONFIG_MTD_UBI_FASTMAP
+ /* We have to enqueue e only if fastmap is disabled,
+ * is fastmap enabled prot_queue_add() will be called by
+ * ubi_wl_get_peb() after removing e from the pool. */
prot_queue_add(ubi, e);
- spin_unlock(&ubi->wl_lock);
-
+#endif
err = ubi_self_check_all_ff(ubi, e->pnum, ubi->vid_hdr_aloffset,
ubi->peb_size - ubi->vid_hdr_aloffset);
if (err) {
@@ -404,6 +551,150 @@ retry:
return e->pnum;
}

+#ifdef CONFIG_MTD_UBI_FASTMAP
+/**
+ * return_unused_pool_pebs - returns unused PEB to the free tree.
+ * @ubi: UBI device description object
+ * @pool: fastmap pool description object
+ */
+static void return_unused_pool_pebs(struct ubi_device *ubi,
+ struct ubi_fm_pool *pool)
+{
+ int i;
+ struct ubi_wl_entry *e;
+
+ for (i = pool->used; i < pool->size; i++) {
+ e = ubi->lookuptbl[pool->pebs[i]];
+ wl_tree_add(e, &ubi->free);
+ ubi->free_count++;
+ }
+}
+
+/**
+ * refill_wl_pool - refills all the fastmap pool used by the
+ * WL sub-system.
+ * @ubi: UBI device description object
+ */
+static void refill_wl_pool(struct ubi_device *ubi)
+{
+ struct ubi_wl_entry *e;
+ struct ubi_fm_pool *pool = &ubi->fm_wl_pool;
+
+ return_unused_pool_pebs(ubi, pool);
+
+ for (pool->size = 0; pool->size < pool->max_size; pool->size++) {
+ if (!ubi->free.rb_node ||
+ (ubi->free_count - ubi->beb_rsvd_pebs < 5))
+ break;
+
+ e = find_wl_entry(ubi, &ubi->free, WL_FREE_MAX_DIFF);
+ self_check_in_wl_tree(ubi, e, &ubi->free);
+ rb_erase(&e->u.rb, &ubi->free);
+ ubi->free_count--;
+
+ pool->pebs[pool->size] = e->pnum;
+ }
+ pool->used = 0;
+}
+
+/**
+ * refill_wl_user_pool - refills all the fastmap pool used by ubi_wl_get_peb.
+ * @ubi: UBI device description object
+ */
+static void refill_wl_user_pool(struct ubi_device *ubi)
+{
+ struct ubi_fm_pool *pool = &ubi->fm_pool;
+
+ return_unused_pool_pebs(ubi, pool);
+
+ for (pool->size = 0; pool->size < pool->max_size; pool->size++) {
+ if (!ubi->free.rb_node ||
+ (ubi->free_count - ubi->beb_rsvd_pebs < 1))
+ break;
+
+ pool->pebs[pool->size] = __wl_get_peb(ubi);
+ if (pool->pebs[pool->size] < 0)
+ break;
+ }
+ pool->used = 0;
+}
+
+/**
+ * ubi_refill_pools - refills all fastmap PEB pools.
+ * @ubi: UBI device description object
+ */
+void ubi_refill_pools(struct ubi_device *ubi)
+{
+ spin_lock(&ubi->wl_lock);
+ refill_wl_pool(ubi);
+ refill_wl_user_pool(ubi);
+ spin_unlock(&ubi->wl_lock);
+}
+
+/* ubi_wl_get_peb - works exaclty like __wl_get_peb but keeps track of
+ * the fastmap pool.
+ */
+int ubi_wl_get_peb(struct ubi_device *ubi)
+{
+ int ret;
+ struct ubi_fm_pool *pool = &ubi->fm_pool;
+ struct ubi_fm_pool *wl_pool = &ubi->fm_wl_pool;
+
+ if (!pool->size || !wl_pool->size || pool->used == pool->size ||
+ wl_pool->used == wl_pool->size)
+ ubi_update_fastmap(ubi);
+
+ /* we got not a single free PEB */
+ if (!pool->size)
+ ret = -ENOSPC;
+ else {
+ spin_lock(&ubi->wl_lock);
+ ret = pool->pebs[pool->used++];
+ prot_queue_add(ubi, ubi->lookuptbl[ret]);
+ spin_unlock(&ubi->wl_lock);
+ }
+
+ return ret;
+}
+
+/* get_peb_for_wl - returns a PEB to be used internally by the WL sub-system.
+ *
+ * @ubi: UBI device description object
+ */
+static struct ubi_wl_entry *get_peb_for_wl(struct ubi_device *ubi)
+{
+ struct ubi_fm_pool *pool = &ubi->fm_wl_pool;
+ int pnum;
+
+ if (pool->used == pool->size || !pool->size) {
+ /* We cannot update the fastmap here because this
+ * function is called in atomic context.
+ * Let's fail here and refill/update it as soon as possible. */
+ schedule_work(&ubi->fm_work);
+ return NULL;
+ } else {
+ pnum = pool->pebs[pool->used++];
+ return ubi->lookuptbl[pnum];
+ }
+}
+#else
+static struct ubi_wl_entry *get_peb_for_wl(struct ubi_device *ubi)
+{
+ return find_wl_entry(ubi, &ubi->free, WL_FREE_MAX_DIFF);
+}
+
+int ubi_wl_get_peb(struct ubi_device *ubi)
+{
+ int peb;
+
+ spin_lock(&ubi->wl_lock);
+ peb = __wl_get_peb(ubi);
+ spin_unlock(&ubi->wl_lock);
+
+ return peb;
+}
+#endif
+
/**
* prot_queue_del - remove a physical eraseblock from the protection queue.
* @ubi: UBI device description object
@@ -534,14 +825,14 @@ repeat:
}

/**
- * schedule_ubi_work - schedule a work.
+ * __schedule_ubi_work - schedule a work.
* @ubi: UBI device description object
* @wrk: the work to schedule
*
* This function adds a work defined by @wrk to the tail of the pending works
- * list.
+ * list. Can only be used of ubi->work_sem is already held in read mode!
*/
-static void schedule_ubi_work(struct ubi_device *ubi, struct ubi_work *wrk)
+static void __schedule_ubi_work(struct ubi_device *ubi, struct ubi_work *wrk)
{
spin_lock(&ubi->wl_lock);
list_add_tail(&wrk->list, &ubi->works);
@@ -552,9 +843,35 @@ static void schedule_ubi_work(struct ubi_device *ubi, struct ubi_work *wrk)
spin_unlock(&ubi->wl_lock);
}

+/**
+ * schedule_ubi_work - schedule a work.
+ * @ubi: UBI device description object
+ * @wrk: the work to schedule
+ *
+ * This function adds a work defined by @wrk to the tail of the pending works
+ * list.
+ */
+static void schedule_ubi_work(struct ubi_device *ubi, struct ubi_work *wrk)
+{
+ down_read(&ubi->work_sem);
+ __schedule_ubi_work(ubi, wrk);
+ up_read(&ubi->work_sem);
+}
+
static int erase_worker(struct ubi_device *ubi, struct ubi_work *wl_wrk,
int cancel);

+#ifdef CONFIG_MTD_UBI_FASTMAP
+/**
+ * ubi_is_erase_work - checks whether a work is erase work.
+ * @wrk: The work object to be checked
+ */
+int ubi_is_erase_work(struct ubi_work *wrk)
+{
+ return wrk->func == erase_worker;
+}
+#endif
+
/**
* schedule_erase - schedule an erase work.
* @ubi: UBI device description object
@@ -571,6 +888,9 @@ static int schedule_erase(struct ubi_device *ubi, struct ubi_wl_entry *e,
{
struct ubi_work *wl_wrk;

+ ubi_assert(e);
+ ubi_assert(!ubi_is_fm_block(ubi, e->pnum));
+
dbg_wl("schedule erasure of PEB %d, EC %d, torture %d",
e->pnum, e->ec, torture);

@@ -589,6 +909,79 @@ static int schedule_erase(struct ubi_device *ubi, struct ubi_wl_entry *e,
}

/**
+ * do_sync_erase - run the erase worker synchronously.
+ * @ubi: UBI device description object
+ * @e: the WL entry of the physical eraseblock to erase
+ * @vol_id: the volume ID that last used this PEB
+ * @lnum: the last used logical eraseblock number for the PEB
+ * @torture: if the physical eraseblock has to be tortured
+ *
+ */
+static int do_sync_erase(struct ubi_device *ubi, struct ubi_wl_entry *e,
+ int vol_id, int lnum, int torture)
+{
+ struct ubi_work *wl_wrk;
+
+ dbg_wl("sync erase of PEB %i", e->pnum);
+
+ wl_wrk = kmalloc(sizeof(struct ubi_work), GFP_NOFS);
+ if (!wl_wrk)
+ return -ENOMEM;
+
+ wl_wrk->e = e;
+ wl_wrk->vol_id = vol_id;
+ wl_wrk->lnum = lnum;
+ wl_wrk->torture = torture;
+
+ return erase_worker(ubi, wl_wrk, 0);
+}
+
+#ifdef CONFIG_MTD_UBI_FASTMAP
+/**
+ * ubi_wl_put_fm_peb - returns a PEB used in a fastmap to the wear-leveling
+ * sub-system.
+ * see: ubi_wl_put_peb()
+ *
+ * @ubi: UBI device description object
+ * @fm_e: physical eraseblock to return
+ * @lnum: the last used logical eraseblock number for the PEB
+ * @torture: if this physical eraseblock has to be tortured
+ */
+int ubi_wl_put_fm_peb(struct ubi_device *ubi, struct ubi_wl_entry *fm_e,
+ int lnum, int torture)
+{
+ struct ubi_wl_entry *e;
+ int vol_id, pnum = fm_e->pnum;
+
+ dbg_wl("PEB %d", pnum);
+
+ ubi_assert(pnum >= 0);
+ ubi_assert(pnum < ubi->peb_count);
+
+ spin_lock(&ubi->wl_lock);
+ e = ubi->lookuptbl[pnum];
+
+ /* This can happen if we recovered from a fastmap the very
+ * first time and writing now a new one. In this case the wl system
+ * has never seen any PEB used by the original fastmap.
+ */
+ if (!e) {
+ e = fm_e;
+ ubi_assert(e->ec >= 0);
+ ubi->lookuptbl[pnum] = e;
+ } else {
+ e->ec = fm_e->ec;
+ kfree(fm_e);
+ }
+
+ spin_unlock(&ubi->wl_lock);
+
+ vol_id = lnum ? UBI_FM_DATA_VOLUME_ID : UBI_FM_SB_VOLUME_ID;
+ return schedule_erase(ubi, e, vol_id, lnum, torture);
+}
+#endif
+
+/**
* wear_leveling_worker - wear-leveling worker function.
* @ubi: UBI device description object
* @wrk: the work object
@@ -602,10 +995,11 @@ static int wear_leveling_worker(struct ubi_device *ubi, struct ubi_work *wrk,
int cancel)
{
int err, scrubbing = 0, torture = 0, protect = 0, erroneous = 0;
- int vol_id = -1, uninitialized_var(lnum);
+ int anchor, vol_id = -1, uninitialized_var(lnum);
struct ubi_wl_entry *e1, *e2;
struct ubi_vid_hdr *vid_hdr;

+ anchor = wrk->anchor;
kfree(wrk);
if (cancel)
return 0;
@@ -636,14 +1030,35 @@ static int wear_leveling_worker(struct ubi_device *ubi, struct ubi_work *wrk,
goto out_cancel;
}

+#ifdef CONFIG_MTD_UBI_FASTMAP
+ /* Check whether we need to produce an anchor PEB */
+ if (!anchor)
+ anchor = !anchor_pebs_avalible(&ubi->free);
+
+ if (anchor) {
+ e1 = find_anchor_wl_entry(&ubi->used);
+ if (!e1)
+ goto out_cancel;
+ e2 = get_peb_for_wl(ubi);
+ if (!e2)
+ goto out_cancel;
+
+ self_check_in_wl_tree(ubi, e1, &ubi->used);
+ rb_erase(&e1->u.rb, &ubi->used);
+ dbg_wl("anchor-move PEB %d to PEB %d", e1->pnum, e2->pnum);
+ } else if (!ubi->scrub.rb_node) {
+#else
if (!ubi->scrub.rb_node) {
+#endif
/*
* Now pick the least worn-out used physical eraseblock and a
* highly worn-out free physical eraseblock. If the erase
* counters differ much enough, start wear-leveling.
*/
e1 = rb_entry(rb_first(&ubi->used), struct ubi_wl_entry, u.rb);
- e2 = find_wl_entry(&ubi->free, WL_FREE_MAX_DIFF);
+ e2 = get_peb_for_wl(ubi);
+ if (!e2)
+ goto out_cancel;

if (!(e2->ec - e1->ec >= UBI_WL_THRESHOLD)) {
dbg_wl("no WL needed: min used EC %d, max free EC %d",
@@ -658,14 +1073,15 @@ static int wear_leveling_worker(struct ubi_device *ubi, struct ubi_work *wrk,
/* Perform scrubbing */
scrubbing = 1;
e1 = rb_entry(rb_first(&ubi->scrub), struct ubi_wl_entry, u.rb);
- e2 = find_wl_entry(&ubi->free, WL_FREE_MAX_DIFF);
+ e2 = get_peb_for_wl(ubi);
+ if (!e2)
+ goto out_cancel;
+
self_check_in_wl_tree(ubi, e1, &ubi->scrub);
rb_erase(&e1->u.rb, &ubi->scrub);
dbg_wl("scrub PEB %d to PEB %d", e1->pnum, e2->pnum);
}

- self_check_in_wl_tree(ubi, e2, &ubi->free);
- rb_erase(&e2->u.rb, &ubi->free);
ubi->move_from = e1;
ubi->move_to = e2;
spin_unlock(&ubi->wl_lock);
@@ -782,7 +1198,7 @@ static int wear_leveling_worker(struct ubi_device *ubi, struct ubi_work *wrk,
ubi->move_to_put = ubi->wl_scheduled = 0;
spin_unlock(&ubi->wl_lock);

- err = schedule_erase(ubi, e1, vol_id, lnum, 0);
+ err = do_sync_erase(ubi, e1, vol_id, lnum, 0);
if (err) {
kmem_cache_free(ubi_wl_entry_slab, e1);
if (e2)
@@ -797,7 +1213,7 @@ static int wear_leveling_worker(struct ubi_device *ubi, struct ubi_work *wrk,
*/
dbg_wl("PEB %d (LEB %d:%d) was put meanwhile, erase",
e2->pnum, vol_id, lnum);
- err = schedule_erase(ubi, e2, vol_id, lnum, 0);
+ err = do_sync_erase(ubi, e2, vol_id, lnum, 0);
if (err) {
kmem_cache_free(ubi_wl_entry_slab, e2);
goto out_ro;
@@ -836,7 +1252,7 @@ out_not_moved:
spin_unlock(&ubi->wl_lock);

ubi_free_vid_hdr(ubi, vid_hdr);
- err = schedule_erase(ubi, e2, vol_id, lnum, torture);
+ err = do_sync_erase(ubi, e2, vol_id, lnum, torture);
if (err) {
kmem_cache_free(ubi_wl_entry_slab, e2);
goto out_ro;
@@ -877,12 +1293,13 @@ out_cancel:
/**
* ensure_wear_leveling - schedule wear-leveling if it is needed.
* @ubi: UBI device description object
+ * @nested: set to non-zero if this function is called from UBI worker
*
* This function checks if it is time to start wear-leveling and schedules it
* if yes. This function returns zero in case of success and a negative error
* code in case of failure.
*/
-static int ensure_wear_leveling(struct ubi_device *ubi)
+static int ensure_wear_leveling(struct ubi_device *ubi, int nested)
{
int err = 0;
struct ubi_wl_entry *e1;
@@ -910,7 +1327,7 @@ static int ensure_wear_leveling(struct ubi_device *ubi)
* %UBI_WL_THRESHOLD.
*/
e1 = rb_entry(rb_first(&ubi->used), struct ubi_wl_entry, u.rb);
- e2 = find_wl_entry(&ubi->free, WL_FREE_MAX_DIFF);
+ e2 = find_wl_entry(ubi, &ubi->free, WL_FREE_MAX_DIFF);

if (!(e2->ec - e1->ec >= UBI_WL_THRESHOLD))
goto out_unlock;
@@ -927,8 +1344,12 @@ static int ensure_wear_leveling(struct ubi_device *ubi)
goto out_cancel;
}

+ wrk->anchor = 0;
wrk->func = &wear_leveling_worker;
- schedule_ubi_work(ubi, wrk);
+ if (nested)
+ __schedule_ubi_work(ubi, wrk);
+ else
+ schedule_ubi_work(ubi, wrk);
return err;

out_cancel:
@@ -939,6 +1360,38 @@ out_unlock:
return err;
}

+#ifdef CONFIG_MTD_UBI_FASTMAP
+/**
+ * ubi_ensure_anchor_pebs - schedule wear-leveling to produce an anchor PEB.
+ * @ubi: UBI device description object
+ */
+int ubi_ensure_anchor_pebs(struct ubi_device *ubi)
+{
+ struct ubi_work *wrk;
+
+ spin_lock(&ubi->wl_lock);
+ if (ubi->wl_scheduled) {
+ spin_unlock(&ubi->wl_lock);
+ return 0;
+ }
+ ubi->wl_scheduled = 1;
+ spin_unlock(&ubi->wl_lock);
+
+ wrk = kmalloc(sizeof(struct ubi_work), GFP_NOFS);
+ if (!wrk) {
+ spin_lock(&ubi->wl_lock);
+ ubi->wl_scheduled = 0;
+ spin_unlock(&ubi->wl_lock);
+ return -ENOMEM;
+ }
+
+ wrk->anchor = 1;
+ wrk->func = &wear_leveling_worker;
+ schedule_ubi_work(ubi, wrk);
+ return 0;
+}
+#endif
+
/**
* erase_worker - physical eraseblock erase worker function.
* @ubi: UBI device description object
@@ -969,6 +1422,8 @@ static int erase_worker(struct ubi_device *ubi, struct ubi_work *wl_wrk,
dbg_wl("erase PEB %d EC %d LEB %d:%d",
pnum, e->ec, wl_wrk->vol_id, wl_wrk->lnum);

+ ubi_assert(!ubi_is_fm_block(ubi, e->pnum));
+
err = sync_erase(ubi, e, wl_wrk->torture);
if (!err) {
/* Fine, we've erased it successfully */
@@ -976,6 +1431,7 @@ static int erase_worker(struct ubi_device *ubi, struct ubi_work *wl_wrk,

spin_lock(&ubi->wl_lock);
wl_tree_add(e, &ubi->free);
+ ubi->free_count++;
spin_unlock(&ubi->wl_lock);

/*
@@ -985,7 +1441,7 @@ static int erase_worker(struct ubi_device *ubi, struct ubi_work *wl_wrk,
serve_prot_queue(ubi);

/* And take care about wear-leveling */
- err = ensure_wear_leveling(ubi);
+ err = ensure_wear_leveling(ubi, 1);
return err;
}

@@ -1223,7 +1679,7 @@ retry:
* Technically scrubbing is the same as wear-leveling, so it is done
* by the WL worker.
*/
- return ensure_wear_leveling(ubi);
+ return ensure_wear_leveling(ubi, 0);
}

/**
@@ -1404,7 +1860,7 @@ static void cancel_pending(struct ubi_device *ubi)
*/
int ubi_wl_init(struct ubi_device *ubi, struct ubi_attach_info *ai)
{
- int err, i;
+ int err, i, reserved_pebs, found_pebs = 0;
struct rb_node *rb1, *rb2;
struct ubi_ainf_volume *av;
struct ubi_ainf_peb *aeb, *tmp;
@@ -1416,6 +1872,9 @@ int ubi_wl_init(struct ubi_device *ubi, struct ubi_attach_info *ai)
init_rwsem(&ubi->work_sem);
ubi->max_ec = ai->max_ec;
INIT_LIST_HEAD(&ubi->works);
+#ifdef CONFIG_MTD_UBI_FASTMAP
+ INIT_WORK(&ubi->fm_work, update_fastmap_work_fn);
+#endif

sprintf(ubi->bgt_name, UBI_BGT_NAME_PATTERN, ubi->ubi_num);

@@ -1437,13 +1896,17 @@ int ubi_wl_init(struct ubi_device *ubi, struct ubi_attach_info *ai)

e->pnum = aeb->pnum;
e->ec = aeb->ec;
+ ubi_assert(!ubi_is_fm_block(ubi, e->pnum));
ubi->lookuptbl[e->pnum] = e;
if (schedule_erase(ubi, e, aeb->vol_id, aeb->lnum, 0)) {
kmem_cache_free(ubi_wl_entry_slab, e);
goto out_free;
}
+
+ found_pebs++;
}

+ ubi->free_count = 0;
list_for_each_entry(aeb, &ai->free, u.list) {
cond_resched();

@@ -1454,8 +1917,14 @@ int ubi_wl_init(struct ubi_device *ubi, struct ubi_attach_info *ai)
e->pnum = aeb->pnum;
e->ec = aeb->ec;
ubi_assert(e->ec >= 0);
+ ubi_assert(!ubi_is_fm_block(ubi, e->pnum));
+
wl_tree_add(e, &ubi->free);
+ ubi->free_count++;
+
ubi->lookuptbl[e->pnum] = e;
+
+ found_pebs++;
}

ubi_rb_for_each_entry(rb1, av, &ai->volumes, rb) {
@@ -1469,6 +1938,7 @@ int ubi_wl_init(struct ubi_device *ubi, struct ubi_attach_info *ai)
e->pnum = aeb->pnum;
e->ec = aeb->ec;
ubi->lookuptbl[e->pnum] = e;
+
if (!aeb->scrub) {
dbg_wl("add PEB %d EC %d to the used tree",
e->pnum, e->ec);
@@ -1478,22 +1948,38 @@ int ubi_wl_init(struct ubi_device *ubi, struct ubi_attach_info *ai)
e->pnum, e->ec);
wl_tree_add(e, &ubi->scrub);
}
+
+ found_pebs++;
}
}

- if (ubi->avail_pebs < WL_RESERVED_PEBS) {
+ dbg_wl("found %i PEBs", found_pebs);
+
+ if (ubi->fm)
+ ubi_assert(ubi->good_peb_count == \
+ found_pebs + ubi->fm->used_blocks);
+ else
+ ubi_assert(ubi->good_peb_count == found_pebs);
+
+ reserved_pebs = WL_RESERVED_PEBS;
+#ifdef CONFIG_MTD_UBI_FASTMAP
+ /* Reserve enough LEBs to store two fastmaps. */
+ reserved_pebs += (ubi->fm_size / ubi->leb_size) * 2;
+#endif
+
+ if (ubi->avail_pebs < reserved_pebs) {
ubi_err("no enough physical eraseblocks (%d, need %d)",
- ubi->avail_pebs, WL_RESERVED_PEBS);
+ ubi->avail_pebs, reserved_pebs);
if (ubi->corr_peb_count)
ubi_err("%d PEBs are corrupted and not used",
ubi->corr_peb_count);
goto out_free;
}
- ubi->avail_pebs -= WL_RESERVED_PEBS;
- ubi->rsvd_pebs += WL_RESERVED_PEBS;
+ ubi->avail_pebs -= reserved_pebs;
+ ubi->rsvd_pebs += reserved_pebs;

/* Schedule wear-leveling if needed */
- err = ensure_wear_leveling(ubi);
+ err = ensure_wear_leveling(ubi, 0);
if (err)
goto out_free;

@@ -1572,7 +2058,7 @@ static int self_check_ec(struct ubi_device *ubi, int pnum, int ec)
}

read_ec = be64_to_cpu(ec_hdr->ec);
- if (ec != read_ec) {
+ if (ec != read_ec && read_ec - ec > 1) {
ubi_err("self-check failed for PEB %d", pnum);
ubi_err("read EC is %lld, should be %d", read_ec, ec);
dump_stack();
--
1.7.6.5

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